- North Korea claimed this week to have tested a hydrogen bomb
- Authors: International community should apply lessons of Iran deal with North Korea
Patricia Lewis is research director of International Security at Chatham House. Beyza Unal is a Nuclear Weapons Policy Research Fellow in Chatham House's International Security Department. The views expressed are their own.
(CNN)Thirteen years ago, North Korea announced its withdrawal from the global nuclear Non-Proliferation Treaty (NPT). Up until last week, it had since conducted three underground nuclear test blasts, despite strict international sanctions aimed at its nuclear program and almost universal condemnation of each test.